In the machining or grinding or rebuilding of a generally cylindrical heavy metal workpiece such as a large diameter cylinder or shaft, it is common to position the workpiece within a machine tool facility similar to a lathe and having one or more workpiece supports mounted on a long base or bed of the machine tool for rotatably supporting an intermediate portion of the workpiece. The workpiece is usually rotated or driven by a motor driven headstock which grips and supports one end of the workpiece, and the opposite end of the workpiece is engaged by a tailstock also mounted on the bed. When the workpiece or shaft has a substantially large diameter or substantial length, for example, a length over forty or fifty feet, the cost of constructing a machine tool facility with a long bed supporting a power driven headstock, one or more intermediate workpiece supports and a tailstock, becomes exceedingly high, and the facility is not easily modified or adjusted for handling workpieces of different diameters and lengths.